乳与乳制品中硫氰酸盐含量的分光光度法测定

Determination of thiocyanate in milk and dairy products by spectrophotometry

目的:建立分光光度法测定乳与乳制品中硫氰酸盐含量的方法。方法:样品经处理后,在中性介质中,于50℃条件下,样品中硫氰酸根与氯胺T反应生成氯化氰,再与异烟酸作用,经水解后生成戊烯二醛,最后与吡唑啉酮缩合生成蓝色染料,该蓝色染料的吸光度与硫氰酸根的浓度在一定范围内呈线性关系,以此测定样品中硫氰酸根的浓度。结果:该方法硫氰酸盐浓度在0.0 mg/L～1.0 mg/L呈线性关系,相关系数为0.9997,检出限为0.02 mg/kg,相对标准偏差在3.48%,样品加标回收率为90.8%。结论:该法操作简单,灵敏度高,准确可靠,适用于乳制品的质量监测。

Objective：To establish a method for the determination of thiocyanate in milk and diary products by spectrophotometry.Methods：After extraction of sample,the thiocyanate in sample reacted with chloramine T to form cyanogen chloride in neutral medium at 50℃.Cyanogen chloride reacted with isonicotinic acid and then hydrolyzed to form glutaconaldehyde which reacted with pyrazolone to form blue dye.The thiocyanate content had positive correlation with blue dye＇s absorbance in a certain range.Results：The range of linear relationship of thiocyanate was 0.0 mg/L～1.0 mg/L（r=0.9997）.The detection limit was 0.02 mg/kg.The RSD was 3.48%.The standard recovery rate was 90.8%.Conclusion：The method is simple,sensitive and accurate,which is suitable for the quality monitoring of dairy products.